ABSTRACT
Objective To assess the diagnostic value of chronotropic index in identifying coronary artery disease (CAD). Methods One hundred and sixty two patients with suspected CAD were referred for a routine treadmill exercise electrocardiogram and subsequently underwent selective coronary angiography within 3 weeks. The magnitude of ST segment depression and chronotropic index were measured by a computerized ECG system. CAD was defined by coronary angiography. Results In detecting CAD, the sensitivity was 70. 1% versus 60.9% (P< 0.05) ,the specificity was 84.0% versus 73.3% (P<0.05), and the accuracy was 76.5% versus 66.7% (P< 0.05) by chronotropic index and standard electrocardiographic test criteria. The value of Kappa statistic for chrono-tropic index consistency in our experiment was 0.534(>0.4). The number of diseased vessels was correlated with the mean value of chronotropic index. The chronotropic index decreased from 0.88±0.09 in patients without coro-nary disease to 0.68±0.06 in those with 3 vessels involved (P<0.01). A more closed relationship was found be-tween chronotropic index and lesion in the fight coronary artery. Conclusions Chronotropic index is possibly a valu-able positive index for the diagnosis of CAD. The sensitivity,specificity and accuracy of chronotropic index are signif-icandy higher than those of standard electrocardiographic test criteria in identifying CAD.
